Mixing device



y 93 J. J. TFJRNER ET AL 1,813,828

MIXING DEVICE Filed Feb. 10, 1936 3 Sheets-Sheet l INVENTOR JOHN J. TURNER. BY CARL ABSMEIEZR ATTTORNEY July 7, 1931. TURNER ET AL 1,813,828

MIXING DEVI C E Fil'ed Feb. 10, 1950 s Sheets-Sheet 2' (b 79 o 0 0 O 0 0 0 0 79 o W) I: O00 \I 00 O '70 0 00 0 0000 :2? I %8%oo 69 3888 I, C K /I/ %?)00 J73 INVE TOR JOHN .TURNER- BY CARL ABsMElEE- ATTORNEY July 7, 1931. J TURNER ETAL 1,813,828

MIXING DEVICE INVENTOR JOHN J. TURNER- BYW ATTORNEY CARL ABSMEIER.

Patented July 7, [1931 am STATES PATENT OFFIQE JOHN J'. TURNER, OF CHICAGO, AND CARL ABSMEIER, F HAYWOOD, ILLINOIS, AS- SIGNOBS T0 UNITED STATES GYPSUM COMPANY, OF CHICAGO, ILLINOIS, A COB- POIRATION OF ILLINOIS MIXING DEvIcE Application filed February 10, 1930. Serial No. 427,100.

This invention relates to a device for mixing cementitious compositions with water.

In the manufacture of plasterboard, tile, and other gypsum or cementitious products with water, the setting time of the gypsum is so controlled by means of accelerators, that a very rapid setting occurs. ten found desirable to introduce foam and various fibers into the composition by mix ing so as to control the properties of the resulting product. Because of the rapid setting of the composition, it is difiicult to design a satisfactory m-xer because of the fact that the stucco tends to accumulate upon in active surfaces of the mixer and eventually stops up the action thereof so as to make it necessary to shut down the mixer for cleaning. Considerable difliculty has also been experienced in that lumps of material form which have unmixed centers, the latter not being homogeneously mixed with the other ingredients and forming defects in the resulting product.

An object of this invention, therefore, is 2 to provide an improved apparatus of mixing whereby the water is thoroughly incorporated with the gypsum or cementitious composition.

Another object of the invention is to provide an improvedmixer which will not permit stucco to set up on inactive surfaces and will also break up all lumps which might otherwise be formed; also to improve mixing methods and apparatus in other respects hereinafter specified and claimed. Reference is to be had to the accompanying drawings forming a part of this specification, in which Fig. 1 is a sectional elevation of the im- ,proved mixing apparatus,

Fig. 2 is a plan view of the apparatus, Fig. 3 is a plan view charge gates,

Fig. 4 is a sectional view through the apparatus taken on the line 4-4 of Fig. 1,

It is ofof one of the dis-- Fig. 5 is a sectional view through the apparatus on the line 55, of Fig. 1,

Fig. 6 is a sectional view through the apparatus on a large scale, on the line 66 of Fig. 2, and

Fig. 7 is a plan view of one of the discharge screens.

The stucco composition to be mixed with water is introduced onto a belt 10 which is allowed to sag near its delivery pulley 11 to form a water pocket. Water is introduced into the pocket and the stucco composition in dry form is introduced onto the belt 10 and drawn through the water pocket. The dry material is thoroughly soaked and moistened by the. water, and then is conveyed upwardly above thewater level to then pass over the pulley 11, and then down the incilned reach of the belt 12, to pulley 13,- where the material is discharged fromthe belt and dropped into a mixer bowl 14 Shafts 16 and 17 supporting the pulleys 11 and 13 respectively are suitably driven by any means, such as; an electric motor not shown, so a to maintain a substantially uniform speed of the belt 10.

The mixing bowl 14 is preferably in the nature of a shallow cylindrical shell formed into sections 18,,having flanges 19 connected together by suitable bolts 194;, so that sections 18 can be easily removed for cleaning or repairing without disturbing other parts of the a paratus. The bowl sections 18 rest upon a ottom plate '20 which is preferably formed of cast metal. The plate 20 1s preferably provided with a circular tongue 21 formed on its upper surface which engages a similarly shaped groove formed in the bottom of the bowl sections 18, so as to I fix the position of the mixing bowl relative to the bottom 20. Thezbottom plate 20 is provided with outstanding lugs 22 which engage suitable framework 23' arranged to support the mixing apparatus. 'A plate 24 is rigidly secured across the framework 23 These balls aid materially in breakin many lumps of material which may be ormprevent the accumulation of an below the mixing bowl so as to form-a support for a plurality of strips of paper 26,.

such as three in number, WhlCh move on top ofthe plate 24 with a continuous motion so internal, semiclrcular raceway 28 which cooperates with a similar semicircular raceway 29 in the inner lower part of the bowl A frustoconical mixing element 30 is rotatably mounted concentrically section 18.

with the mixing bowl 1 1, and the outer periphery of said element 30 is provided with a semicircular raceway 31. A circular space 32 is provided between the outer periphery of the element 30 and the. raceway 28 to receive a plurality of balls 33 which roll in the raceways. These balls 33 are preferably but not necessarily composed of a metallic interior for the purpose of giving them weight, and this metallic core iscovered by a semi-hard layer of rubber, which has sulficient resiliency to flex slightly and aid in breaking ofi any encrusting layers of plaster of Paris which may form on their surfaces.

ed, and thus insure a uniform and homo- .geneous mixture of the water introduced through a pipe 34 with the plaster of Paris and other ingredients.

- The frusto-conical mixing element 30 is preferably rigidly secured near the bottom of a vertical shaft or spindle 36, the extreme lower end of said shaft being sup-- ported in a suitable step bearing 37 which is removably secured by bolts 38 to the bottom plate 20. Suitable openings 40 are provided in the bottomplate so as to materials under said mixing element 30. crapers41 are mounted diagonally in the lower face of the element for the purpose 'of preventing any accumulation of material between the metal faces and to prevent the escape of material through openings b continuously scraping the material-outwar ly into the space 32.

It is desirable to have the shaft 36 and mixing element 30 rotated continuously at aspeed of 90 t'o.150 R. P.-M. and for this purpose, a motor 42 is supported uponsuitable framework 43, and is connected by a belt 44 to a speed reducer 45 of standard construction. A vertical shaft 46 driven through the speed reducer 45, is provided with a flexible coupling 4:7, connedting said shaft to the shaft 36. A gear is concentrically mounted about theshaft 36 and a clutch 48 is connected'between shaft 46 and said gear, said clutchbein operated by a lever 49 tostopyor start erotatiou cleaning.

of said gear. The gear 50 meshes with an idler gear 51 which is rotatably mounted on a fixed idler shaft 52. The gear 51 meshes with a larger gear 53 which in turnis secured to a shaft 54 having a inion 55 secured to the lower end thereo said pinion meshin with a large internal gear 56 which is rigi ly secured to a sleeve 57 concentrically mounted about the shaft 36.

A collar 58 is secured to the, lower end of sleeve 57 and is rotatably mounted about shaft 36 just above the mixing element 30. A scraper arm 59 is secured to the collar 58 as byscrews 60, said scraper arm having the same shape as the contour of the mixing element 30 so as to scrape said mixing element and prevent the formation of encrust-- ing matter thereon. A second U-shaped arm 62 is secured to the collar 58 diametrically opposite the arm 59, and a semi-flexible arm 63 is secured at its innermost end by a bolt 64 to the arm 62 and midway its end it is loosely received between an up-.

turned forked end 65 formed on the arm 62. The flexible arm 63 is mounted to contact with and scrape the lower surface of a.

arranged to scrape the inside of the mixing bowl 14: and prevent the setting of cementitious material on the inner face of said bowl.

The balls 33 provide a grinding and mixing'action for the material in the mixer. In order to prevent the passage of any lumps of material onto the moving strips of paper 26, we provide a screen plate 69 below the opening or ort 32, one screen being provided for eac strip of paper so that for three strips of paper, three screens will be used as shown 1n Fig. 2. The screens 69 are preferably in the form of a circular plate, having numerous holes or ports 70 formed therein, or screen wire.

lit!

The screen plate 69 is preferably rotatably mounted on the .up er end of a pin 71,

which is rigidly fixe in a port casting 77, by set screw 72. The outer periphery of the screen plate 69 preferably has a bevelled edge 73, so that it'is positively received in a similarly shaped groove formed in theport casting 77 and prevented thereby from movement and vibration. The screen plates 69 may be fixed rigidly adjacent the bottom plate 20. but are preferably in circular form so that they may be rotated manually for the purpose of moving a used portion of;

the screen outwardly into position for easy In order to regulate the flow of plastic material through the port 32, we rovide a gate 75 which is preferably semi-circular in shape, and in the form of a flat plate having a bevelled outer peripheral edge 76* engaging a Wedge shaped groove formed in the port casting 77, the latter being secured by bolts 78 to the bottom .plate- 20. A handle 79 is provided on each gate plate75 so that said gate may be rotated about the central pin 71 to'open and close each discharge port. It will be noted that the gate plate 75 is in close contact with the-screen plate. 69 and the sharp edge 80 of said gate plate serves to scrape off any encrusting material on the bottom of the screen plate,

if so desired. In Fig. 2, it will be noted that two additional gates 81 are provided, oneon each side ofthe mixing bowls, these auxiliary gate plates not being provided with screens but merely serving to permit dumping from the mixing bowl of all material if desired and discharging this material to one side of the machine without falling upon the strips of paper 26. These gates are useful when a mixture of improper composition is received in the mixing bowl and which it is desired to dump without using.

same for the making of board.

. In operation, the dry mixture passes along belt 10 through a sloping pocket containing water and is then discharged in a wet condition into the mixer bowl 14 where it falls upon the frusto-conicalmixing element 30 which is rapidly rotating and serves to throw the material outwardly into the path of the balls 33 where mixing action is obtained. The scraper arms 59, 63 and 67 mounted upon the collar 58 are caused to rotate in the same direction as the mixing element 30 but at a slower speed of 5 to 40 R. P. M. The apparatus is driven through motor 42, belt 44 and speed reducer 4:5 and shaft 46 so as to cause the rotation of shaft 36. The sleeve 57 carrying the collar 58 is operated through clutch 48, gears 50, 51 and 53and pinion 55 meshing with .internal gear 56. The material ground up in the mixing bowl 14; by the balls 33 is caused to pass through screen plates 69, the flow of material through the port opening 32 being controlled by gates 75 manually operated by handles '79, said *gates also serving to clean the bottom surface of the screen plates 69. The thoroughly mixed material alls upon the moving strips of paper 26;

We would state in (conclusion that while the illustrated examples constitute practical embodiments of our invention, we do not wish to limit ourselves precisely-to these details, since manifestly the same may be considerably varied without departing from the spirit of the invention as definedin the appended claims.

Having thus described our invention, we claim as new and desire to secure by Letters Patent 1. In a mixing device, a mixing container,-

a rotary mixing element having mixing surfaces, scraplng means closely ad acent to said rotor and adapted to move relative to said rotary element, and balls arranged around the periphery of said mixing element to aid in the mixing of material in said container.

2. In a mixing device, a mixing container,

a rotor rotatably mounted in said container,

scraping means contacting with said rotor and adapted for movement relative'thereto, a ball movably positioned adjacent the periphery of said rotor and adapted to aid 4. In a mixing device, a mixing container,

a shaft rotatably mounted in said container, a rotor having a frusto-conical surface, a ball race around the periphery of said mixing element, said'container being provided with an outlet port adjacent said ball race, and a ball movably positioned on said ball race and adapted to aid in the mixing action in said container before the material passes through said discharge port.

5. In a mixing device, a mixing container, a cover for said container, a circular mixing element rotatably mounted Within said eontainer, a rotary means for scraping the inside'of said cover and said container, additional rotary means adapted to scrape the surface of mixing element, said container being provided with an outlet port positioned adjacent the periphery of said rotary element, 'a ball race associated with said mixing element, a ball movably arranged'on said ball race and adapted to aid in the mixing action in said container before the material is discharged from said discharge port.

6. In a mixing device, a mixing container,

a circular mixing element rotatably mounted within said container, means for introducing the material to be mixed into said container, scraping means between said rotarymixmg element and said container to tain'er.

mixed material from said container through 'sai7d port.

a rotary mixing element positioned within said container, said container being provided with an'outlet port adjacent the periphery of said rotary element, a rotata 1y mounted screen plate positioned across said discharge port, said screen plate being adapted to be manually rotated for easy cleaning, and a discharge gate associated 'with said screen and a apted to. regulate the flow of material from said mixing con- JOHN J. TURNER. CARL ABSMEIEB.

11 a mixing device, a mixing container, 

